KR20120101101A - Method for classifying radiation emitting, opto-electronic semiconductor components - Google Patents

Abstract

The present invention relates to a method for classifying a radiation emitting optoelectronic semiconductor device (20), said sorting method comprising the steps of: providing a radiation emitting optoelectronic semiconductor device (20), said radiation emitting optoelectronic during operation Determining a chromaticity (8) of light emitted from the semiconductor device (20), and classifying the radiation emitting optoelectronic semiconductor device (20) into a predetermined chromaticity range (6) including the determined chromaticity.

Description

Method for classifying radiation emitting optoelectronic semiconductor devices {METHOD FOR CLASSIFYING RADIATION EMITTING, OPTO-ELECTRONIC SEMICONDUCTOR COMPONENTS}

The present invention relates to a method for classifying radiation emitting optoelectronic semiconductor devices. For example, a light emitting diode, that is, a laser diode or a light emitting diode may be used as the radiation emitting optoelectronic semiconductor device.

In many areas of use where radiation emitting optoelectronic semiconductor devices are used, light colors precisely defined by standards are predetermined. Due to the manufacturing process, color difference may be noticeable in the case of the direct comparison between radiation emitting optoelectronic semiconductor devices according to the type and manufacturer. For this reason, it is often necessary to classify radiation emitting optoelectronic semiconductor devices into staged groups (bins), i.e. to perform binning.

There are already a number of standardized systems for classification.

Publication US 6,900,471 B1 describes a method for classification, in which no chromaticities for which blue chromaticities and correlated color temperatures can be assigned at all can be used.

One further classification scheme known uses ANSI-classification, for example. The advantage of the classification system is that it is a standardized classification system. In addition, the groups of classification schemes are also known as planck curves (referred to as plackian locus or black body-curve) and isothermal judd-lines of the same correlation color temperature. Judd-lines). It is found negative that groups not belonging to the jud-lines or Planck curves are centered over the entire range of color temperature. In addition, the individual groups of standard-LED-application examples are too large in size. It is not possible to subclass groups into subgroups of the same size for more precise classification. As a result, the ANSI-classification scheme still does not cover not only the full chromaticity range but also the full chromaticity range to which a correlated color temperature can be assigned.

An object of the present invention to be solved is to provide a classification method capable of consistently classifying a plurality of different radiation emitting optoelectronic semiconductor devices.

According to at least one method embodiment for classification, a radiation emitting optoelectronic semiconductor device is first provided. As the semiconductor device, for example, a laser diode, a laser diode chip, a light emitting diode or a light emitting diode chip is used.

Subsequent method steps determine the chromaticity of the light emitted from the radiation emitting optoelectronic semiconductor device during operation. In order to determine the chromaticity, for example, a spectrophotometer is used.

In this case, chromaticity determination may be made by referring to an arbitrary color space. In principle, each color space is suitable for clearly describing one color through its chromaticity. However, in order to achieve comparability and reproducibility, the chromaticity is preferably determined in a standardized color space. For example, the chromaticity can be determined in the color space system or in the DIN-color space system of one of the CIE-color space systems.

In a subsequent method step, the classification of the radiation emitting optoelectronic semiconductor device takes place in a predetermined chromaticity range, ie in the group comprising the determined chromaticity.

The color space system used for this purpose is subdivided into groups of chromaticity ranges. Thus, groups in which radiation emitting optoelectronic semiconductor devices can be classified are used as the predetermined chromaticity ranges. The classification is made, for example, by comparing the determined chromaticity with a sub-classified color space into predetermined chromaticity ranges and by assigning a radiation emitting optoelectronic semiconductor element to a predetermined chromaticity range, wherein the predetermined chromaticity range comprises radiation emitting optoelectronic semiconductors. There is a determined chromaticity of the device.

According to at least one method embodiment for classification, the predetermined chromaticity range is selected simultaneously from the group of chromaticity ranges, in which case the chromaticity range of at least one of the chromaticity ranges selected from the group of chromaticity ranges comprises a blue chromaticity. In other words, the predetermined chromaticity ranges—ie, the groups or bins used for classification—include at least one chromaticity range having a blue chromaticity to which a correlated color temperature cannot be assigned.

In the conventional classification schemes described above, chromaticity ranges with a blue chromaticity cannot be used because there are only chromaticity ranges in which they can be assigned a correlated color temperature. In other words, in the classification schemes, the classification of the radiation emitting optoelectronic semiconductor devices ends at the hot-end point of the Planck curve, ie the bluish-white chromaticity.

Preferably the predetermined chromaticity range is selected from a group of chromaticity ranges that span the entire color space or generally the entire color space. In other words, by using the predetermined chromaticity ranges selected from the group of chromaticity ranges, the entire used color space or generally the whole used color space can be constructed, so that each chromaticity can also be assigned to the predetermined chromaticity range. . In this way it is possible to classify completely different semiconductor elements-for example colored light emitting diodes such as red, green, blue or yellow, but white light emitting diodes as well-consistently into groups. The expression "usually" the entire color space means that subranges of the color space, eg in the magenta range of the color space, are not used in some cases.

According to at least one method embodiment according to the invention, at least one of the predetermined chromaticity ranges selected from the group of chromaticity ranges, ie one group of possible groups in which classification can be made, intersects by an extended Planck curve. Or immediately adjacent to the extended Planck curve. The extended Planck curve extends at the hot-end point of the Planck curve. In other words, the Planck curve ending at the hot-end point at which the color temperature progresses indefinitely extends to the range of blue chromaticity at the end point.

In other words, the color space used is penetrated by a composite curve consisting of an extended Planck curve and Planck curve. In this case at least one chromaticity range, preferably a plurality of chromaticity ranges, selected from the group of chromaticity ranges is adjacent to or intersected by the synthesis curve. In this case the composite curve subdivides the color space used into two separate ranges: the range above the curve and the range below the curve. For this purpose the composite curve extends from the edge of the color space to the opposite edge of the color space. In other words, unlike Planck curves, the composite curves do not end in the center of the color space.

Preferably the Planck curve extends at least once continuously differentiable, ie smoothly, by the Planck curve extended at its hot-end point. In other words, the synthesis curve is capable of differentiation at least once at the hot-end point of the Planck curve.

In addition, the synthesis curve may be capable of differentiation twice or multiple times at the hot-end point.

If the synthesis curve is capable of differentiating two successively at the hot-end point, for example, even if the chromaticity ranges are far from the synthesis curve, the magnitudes of the predetermined chromaticity ranges are very uniform. In other words, when observing over the entire color space, there is little or no abrupt size change in the chromaticity ranges.

In this case, in particular, the recognition that the hot-end point (correlation color temperature runs about infinitely) separates the color space into two ranges on a physical basis is the basis of the method described in the present invention: With chromaticities that do not have a correlated color temperature. Planck curve extension or extension in the blue chromaticity direction now also allows for subclassification of color space ranges that cannot be used in conventional classification schemes.

According to at least one method embodiment according to the invention, the extended Planck curve is at least a quadratic spline in the CIE u'v 'color space. In other words, the extended Planck curve is a secondary spline or a relatively higher order spline in the CIE u'v 'color space. Secondary splines prove to be particularly suitable for extending Planck curves. In particular, the second Bezier-Spline proves to be the simplest and most obvious possibility to extend the Planck curve to the blue chromaticity range. In this case, in the CIE u'v 'color space and other color spaces, the transformation of the extended Planck curve can be described by a function different from the spline. However, the inverse transformation to the CIE u'v 'color space again generates an initial spline.

In particular, three points are required for the construction of the secondary spline.

According to at least one method embodiment according to the invention, the hot-end point Tu of the Planck curve is selected as the point for the construction of the spline. In this way the Planck curve extends continuously at the hot-end point.

According to at least one method embodiment according to the invention, a point on the tangent tangent to the Planck curve at the hot-end point is selected as the point P for the construction of the spline. Tangential point selection as above allows the composite curve to be capable of continuous differentiation at hot-end points.

For example, the intersection point of the tangent tangent to the Planck curve at the hot-end point may be selected by the spectral color line. The spectral color line is a line of pure colors from the spectral side, which defines the boundary of the color space-for example a horseshoe-shaped CIE-color space. In this case the bottom of the color space is surrounded by a purple boundary.

According to at least one embodiment according to the present invention, a point on the spectral color line is selected as the point S for constructing the spline. Points having a wavelength of at least 360 nm and at most 410 nm, for example 380 nm-points on the spectral color line, are proved for this purpose. For example, the 380 nm dot is characterized by providing a spectral color with the shortest wavelength that the human eye can discern.

Preferably the secondary spline consists of three points indicated.

The spline can appear in the CIE u'v 'color space, for example:

Spline (t) = Tu * (1-t) ^ 2 + P * t * (1-t) + S * t ^ 2, in which case t consists of [0; 1];

Thus, the expanded Planck curve has a value Tu at the beginning, i.e. t = 0, and at the end point, i.e. t = 1.

The location of the points in the color space, ie the chromaticity and coordinates of the points in the color space, depends on the choice of the color space system. However, the points can be clearly specified in each color space system, so that the method described herein for classifying radiation emitting optoelectronic semiconductor devices depends on the color space. In this case the subclassification into chromaticity ranges only depends on the Planck curve and the extension of the Planck curve to the blue chromaticity range which is physically motivated by the specified construction points.

According to at least one method embodiment according to the present invention, an address is assigned to each chromaticity range selected from the group of chromaticity ranges. In this case, the address has a first parameter that specifies the path length or spacing of the chromaticity range from the hot-end point of the Planck curve along the synthesis curve. In other words, the first parameter is measured along the synthesis curve. In this case the actual length of the corresponding synthetic curve range is determined.

The address also has a second parameter, which specifies the path length of the chromaticity range or the spacing of the chromaticity range from the synthesis curve along the jud-line. The configuration of the jud-lines in this case is extended by the same configuration rules as the Planck curve and the extended Planck curve. For example the lines intersect at right angles to the composite curve, ie the Planck curve as well as the extended Planck curve, in the use of the CIE 1960 (uv) color space. The entire color space can develop from the synthesis curve along the synthesis curve and along the jud-lines, and can be addressed.

Due to the fact that the classification is based only on synthetic curves consisting of Planck only curves and extended Planck curves, the method according to the invention for classification is converted into all known and viable color space systems, and together with, for example, CIE And innovations achievable by other standards committees.

According to at least one method embodiment according to the invention, the magnitude of each chromaticity range selected from the group of chromaticity ranges is chosen such that the observer is not aware of the difference for colors of the same chromaticity range.

In other words, a subclassification into each of the chromaticity ranges is performed so that the viewer is in the same chromaticity ranges that cause the same color perception.

In this case, the size of each chromaticity range is preferably chosen to correspond to the maximum three-step MacAdam Ellipse size. Particularly preferably the magnitude of each chromaticity range selected from the group of chromaticity ranges corresponds to an almost or at most one-step Mcadam deviation ellipse.

Such size can be achieved, for example, by the extension of each chromaticity range selected from the group of chromaticity ranges being at least 0.001 and at most 0.005 along the synthesis curve in the CIE u'v 'color space. In this case, the extension of each chromaticity range selected from the group of chromaticity ranges is at least 0.001 and at most 0.005 along the jud-lines in the CIE u'v 'color space. For example, the extension in two directions is 0.002 in the CIE u'v 'color space. Is selected.

These specifications can be converted to other color spaces. In this case the choice of extension is the only free parameter. In this case, in the present invention, the parameter is selected physically and meaningfully in the sense that the extended chromaticity ranges selected from the group of chromaticity ranges have a size corresponding to a nearly one-step Macadam deviation ellipse.

According to at least one method embodiment according to the invention, information on a predetermined chromaticity range, ie a group classifying a radiation emitting optoelectronic semiconductor device, may be stored in a storage unit, the storage unit being for example radiation It is fixed on a module carrier for the emitting optoelectronic semiconductor device, and in some cases is electrically connected.

As the module carrier, for example, a circuit board such as a printed circuit board or a metal core circuit board can be used, on which the radiation emitting optoelectronic semiconductor element is fixed and electrically connected.

The method described in the present invention for classifying radiation emitting optoelectronic semiconductor devices is described in more detail below with reference to embodiments and the corresponding figures.

The method described in the present invention is described in more detail with reference to FIGS. 1A, 1B, 2A, 2B, 2C, 3.
An optoelectronic semiconductor component having radiation emitting optoelectronic semiconductor devices classified by the method according to the invention is described in more detail with reference to the schematic plan view of FIG. 4.

The same reference numerals have been provided in the drawings to refer to like, like shaped or like acting elements. The mutual size ratios of the figures and elements shown in the figures cannot be considered to be a measure. Rather, individual elements may be shown excessively large for better explanation and / or understanding.

1A shows a graphical representation of the CIE-XY-color space. The horseshoe-shaped color space is surrounded by a spectral color line 2 above and terminated by a purple line 3 below. Planck curve 11 is shown into the color space, which is crossed by jud-lines (isothermal lines) 4. Planck curve 11 extends from the point T0 at which the temperature is 0 K to the point Tu at which the temperature proceeds indefinitely. Planck curve 11 ends in the chromaticity range of bluish white.

In the present invention the Planck curve 11 extends to the synthesis curve 1.

For this purpose, the Planck curve 11 is followed by an extended Planck curve 12 at the hot-end point Tu. In this case, the synthesis curve 1 is preferably at least one continuous differentiation at the point Tu. The extended Planck curve 12 extends from the hot-end point Tu to the point S at a wavelength of 380 nm. In the present invention, the point S is the intersection of the net track locus 3 and the spectral color line 2.

As mentioned above, the conventional method for classifying light emitting diodes, for example, relates only to chromaticities to which a color temperature can be assigned or a correlated color temperature can be assigned by the jud-lines 4. Other chromaticities, like for example blue chromaticity ranges, can now be used for classification via the synthesis curve 1.

In FIG. 1B spectra of black body emitters for different color temperatures are shown. In this case, it can be seen that the curves for one color temperature converge at approximately infinity, i.e. at point Tu. A large exponential rise appears at a temperature T of approximately zero, and the value of "color matching functions" (X, Y, Z) is close to approximately zero at wavelengths of> 800 nm.

In the present invention, the hot-end point Tu is selected as the starting point for constructing the curve coordinate system. In other words, the hot-end point Tu forms the zero point or start of the coordinate system. In this case, according to the advantage that the hot-end point Tu has, the hot-end point is irrelevant to which material the light is incident or not to be incident on, and which material the light passes through. The hot-end point is especially the same for Planck curves in vacuum and air.

The classification method described in the present invention is now described in more detail with reference to the graphical diagram of FIG. 2A. 2a shows the synthesis curve 1. The space is extended by the synthesis curve 1 and the parallel lines 13 and the jud-lines 4 with respect to the synthesis curve 1, which space is parameterized by the indicated two parameters p and j. Where p is the path length on the synthesis curve 1 and j is the path length on the jud-line 4.

In this case, the magnitude of the path lengths p, j can preferably classify the chromaticity 8 of the predetermined chromaticity range 6 (ie, the radiation emitting optoelectronic semiconductor device 20 extending through the path lengths). Group) is chosen to have a size corresponding to a nearly one-step Macadam deviation ellipse 5. In this case variations in the chromaticity 8 within the predetermined chromaticity range 6 cannot be perceived by the observer.

In the CIE u'v 'color space in which the McAdam deviation ellipse is nearly circular, p and j are selected for this purpose, for example, p = 0.002 and j = 0.002. It is also possible to convert the path lengths to other color spaces.

Also shown in FIG. 2A is the ANSI-groups 9. In the figure it can be seen that the ANSI-groups 9 have different sizes and are not centered with respect to the Planck curve 11. In addition, group classification is possible only in a limited range of color spaces.

2b shows an enlarged view of the CIE u'v 'color space including the synthesis curve 1.

The configuration of the extended Planck curve 12 is described in more detail with reference to the graphical diagram of FIG. 2C. As further indicated above, the extended Planck curve 12 is constructed as a Bezier-spline in the CIE u'v 'color space by construction points Tu, P, S. In other words, the spline may appear in the CIE u'v 'color space, for example, as follows.

Spline (t) = Tu * (1-t) ^ 2 + P * t * (1-t) + S * t ^ 2, where t consists of [0; 1];

The first construction point is the hot-end point Tu of the Planck curve 11, the hot-end point being the coordinate u '= 0.1801 in the CIE u'v' color space; v '= 0.3953.

The second construction point S is the point at which the light has a wavelength of 380 nm on the spectral color line 2 in the present invention. The point S has the coordinates u '= 0.2568, v' = 0.0165.

In the present invention, as the third construction point P, the intersection point of the spectral color line 2 and the tangent 14 is selected at the high temperature-end point Tu. The coordinates of the point P are u '= 0.1412, v' = 0.1559.

The selection of the construction points is independent of the color space system used and is therefore particularly well suited for extending the Planck curve 11. However, other meaningful extensions of the Planck curve can also be considered. The classification method described in the present invention also applies to other synthetic curves.

Also shown in FIG. 2C is jud-lines 4, which juddle intersect the synthesis curve at right angles in the CIE − (u ′, v ′) color space. This orthogonality no longer exists in the transformed u'-v'-color space.

Addressing of the predetermined chromaticity range is described in more detail with reference to FIG. 3. The address space of the predetermined chromaticity ranges is extended by the path lengths p and j, as described above.

In the present invention, the following nomenclature is chosen: path lengths p away from the hot-end Tu are positively calculated along the Planck curve 11 and enumerated as pXXX. Case X starts at 1.

The intervals are consecutively numbered nXXX along the extended Planck curve 12.

The spacings correspondingly produced along the jud-lines 4 are listed as jXX above the synthesis curve 1 and kXX below the synthesis curve 1.

The unknown illustrated chromaticity range 6, in which the chromaticity 8 of the radiation emitting semiconductor element is present, therefore has an address p004j03. The predetermined chromaticity range 6 is within a group 7 of relatively large chromaticity ranges, and the address space of the multiple chromaticity ranges can be designated as follows: p002k03-p004j03.

In other words, the method described herein for classifying radiation emitting optoelectronic semiconductor devices makes it possible not only to classify any color space into predetermined chromaticity ranges, but also to achieve consistency of each chromaticity range, ie of each group. Enable addressing. Thus, unique chromaticity ranges 6 or combinations of chromaticity ranges 7 can be specified via unique nomenclature.

4 shows a schematic plan view of an optoelectronic semiconductor component with a module carrier 22. As the module carrier 22, for example, a circuit board such as a metal core circuit board or a printed circuit board is used. On the module carrier 22 is provided a housing 23, for example a ceramic carrier, which supports three radiation emitting optoelectronic semiconductor elements 20, for example a light emitting diode chip.

Each of the semiconductor devices 20 is classified into a predetermined chromaticity range by the method described in the present invention. For example, the light emitted from the semiconductor elements 20 during operation each has a chromaticity, which is classified into the same group.

The measured values detected in the semiconductor devices 20, in other words, for example, addresses of predetermined chromaticity ranges in which the semiconductor devices 20 are classified, are stored in the electronic storage unit 21, and the storage unit is stored in the electronic storage unit 21. Similarly, it is fixed to the module carrier 22 and electrically connected. The component can be contacted from the outside via the connection point 24. Chromaticity information from the storage unit 21 via the access point 24 can also be read.

Overall, the present invention provides a very flexible method for classifying radiation emitting semiconductor devices. The method can be applied to various color space systems. Furthermore, the method can be carried out whether or not the Planck curve is determined in vacuum or in air. In addition, the method can be applied to components that generate other light, such as fluorescent lamps, discharge lamps or electroluminescent lamps.

The present invention is not limited to the above embodiments due to the detailed description with reference to the embodiments. Rather, the invention includes each new feature and each combination of features, in particular each feature combination being included in the claims even if the feature or the combination itself is not expressly described in the claims or the embodiments. To be considered.

This patent application claims the priority of German patent application 102009056665.1, the disclosure of which priority document is hereby incorporated by reference.

Claims (15)

A method for classifying radiation emitting optoelectronic semiconductor devices,
Providing a radiation emitting optoelectronic semiconductor device 20,
Determining the chromaticity 8 of the light emitted from the radiation emitting optoelectronic semiconductor device 20 during operation,
Classifying the radiation emitting optoelectronic semiconductor device 20 into a predetermined chromaticity range 6 comprising the determined chromaticity, wherein the predetermined chromaticity range 6 is selected from a group of chromaticity ranges 7, The chromaticity range of at least one of the chromaticity ranges selected from the group of chromaticity ranges comprises a blue chromaticity and / or a chromaticity to which a correlated color temperature cannot be assigned;
/ RTI >
A method for classifying radiation emitting optoelectronic semiconductor devices. The method of claim 1,
The chromaticity range of at least one of the chromaticity ranges selected from the group of chromaticity ranges 7 is intersected by the extended Planck curve 12 or adjacent to the extended Planck curve 12 and the extended Planck curve ( 12) extends at the hot-end point Tu of the Planck curve 11 and forms a composite curve 1 with the Planck curve 11,
A method for classifying radiation emitting optoelectronic semiconductor devices. The method of claim 2,
The extended Planck curve 12 extends at least once in successive differentiation at the hot-end point Tu of the Planck curve 11,
A method for classifying radiation emitting optoelectronic semiconductor devices. The method of claim 3, wherein
The expanded Planck curve 12 in the CIE u'v 'color space is at least a secondary spline,
A method for classifying radiation emitting optoelectronic semiconductor devices. The method of claim 4, wherein
The expanded Planck curve 12 in the CIE u'v 'color space is a secondary Bezier-spline,
A method for classifying radiation emitting optoelectronic semiconductor devices. The method according to claim 4 or 5,
The point Tu for constructing the spline is the hot-end point of the Planck curve 11,
A method for grouping radiation emitting optoelectronic semiconductor devices. The method according to any one of claims 4 to 6,
The point P for constructing the spline is a point on the tangent 14 that abuts the Planck curve 12 at the hot-end point Tu,
A method for classifying radiation emitting optoelectronic semiconductor devices. 8. The method according to any one of claims 4 to 7,
The point S for constructing the spline is on the spectral color line 2,
A method for classifying radiation emitting optoelectronic semiconductor devices. 9. The method according to any one of claims 1 to 8,
Each chromaticity range selected from the group of chromaticity ranges 7 is assigned an address,
Said address having a first parameter p, said first parameter specifying an interval of chromaticity range from the hot-end point Tu of said Planck curve 12 along said synthesis curve 1, and
The address has a second parameter j, which specifies an interval of chromaticity range along the jud-line 4 from the synthesis curve 1,
A method for classifying radiation emitting optoelectronic semiconductor devices. 10. The method according to any one of claims 1 to 9,
The magnitude of each chromaticity range selected from the group of chromaticity ranges 7 is chosen such that the observer is not aware of the difference at all for colors of the same chromaticity range.
A method for classifying radiation emitting optoelectronic semiconductor devices. 11. The method according to any one of claims 1 to 10,
The magnitude of each chromaticity range selected from the group of chromaticity ranges 7 corresponds to a maximum three-step Macadam deviation ellipse,
A method for classifying radiation emitting optoelectronic semiconductor devices. 12. The method according to any one of claims 1 to 11,
The magnitude of each chromaticity range selected from the group of chromaticity ranges 7 is about the same or the same as the one-stage Macadam deviation ellipse 5,
A method for classifying radiation emitting optoelectronic semiconductor devices. The method according to any one of claims 1 to 12,
The extension p of each chromaticity range selected from the group of chromaticity ranges 7 is at least 0.001 and at most 0.005 in the CIE u'v 'color space, as measured along the synthesis curve.
A method for classifying radiation emitting optoelectronic semiconductor devices. 14. The method according to any one of claims 1 to 13,
The extension j of each chromaticity range selected from the group of chromaticity ranges 7 is at least 0.001 and at most 0.005 in the CIE u'v 'color space, measured along the jud-line 4.
A method for classifying radiation emitting optoelectronic semiconductor devices. The method according to any one of claims 1 to 14,
Measurement values for the predetermined chromaticity range 6 are stored in a storage unit 21, which is fixed on the module carrier 22 for the radiation emitting optoelectronic semiconductor device 20 to electrically Connected to,
A method for classifying radiation emitting optoelectronic semiconductor devices.

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